How can i get a correct the diagnosis of sinus infection or dental problem and what specialists do i need to talk to?

Ent first: Best to see an ENT first if no findings then comprehensive exam and xr with dds.

Self Evaluation of: Symptoms first -/ is the primary pain dental or are you congested, post nasal drip ... If the dental issue is primary then probably would start off with a dental evaluation / x-rays if you haven't seen a dentist in a while. If its not dental in etiology then a visit to your pcp or ENT would be recommended. Hope this helps.

See a dentist : A "dental sinus" usually results from a chronic infection in long-lasting necrotic dental pulp (a dead tooth). Dental treatment (e.g. root canal) is the only successful treatment for a "dental sinus". Call a dentist today.